Electricity and water: Maybe not a great mix

Electricity is so readily available that we take it nearly for granted. Much of the debate over our electricity sources is focused on climate impacts or air pollution. I have written about both of these issues in earlier columns. One less discussed resource affected by electricity generation is water.

Water and electricity are intimately connected in many ways. All of our methods of producing electricity consume water. This consumption can be direct, such as through the boiling of water in a coal, nuclear or natural gas plant to turn the turbines that generated the electricity. Or it can be indirect, such as the water used in photovoltaic cell production to keep the materials clean. Most of our electricity sources have a mixture of direct and indirect water uses.

Some sources of electricity require more water than others, often tremendous amounts more. If we want to treat water as the valuable resource it is, we must look at our energy choices.

According to the U.S. Geological Survey, 53 percent of all of the fresh surface water use in the U.S. in 2005 was connected to the electrical grid. River Network estimates that the average person in the U.S. uses up to five times more water through his or her electricity use than through his or her more direct water consumption (cooking, toilets, washing the car and even the lawn).

In northwestern New Mexico, the Four Corners Power Plant and San Juan Generating Station draw over 46,500 acre-feet of water per year from the San Juan River to cool the plants to burn coal.

The amount of consumptive use in New Mexico in the San Juan Basin on average is approximately 642,000 acre-feet per year, based on the U.S. Bureau of Reclamation 2007 Hydrologic Determination. Therefore, almost 7 percent of the allocated water for consumptive use in the San Juan Basin is used for the northwest New Mexico coal plants.

This industrial water use, which equates to more than 15 billion gallons of water per year, represents a vast use of water at a time where we are recognizing the extreme drought conditions and the fragility of the landscape where we live.

While every power plant and every solar panel factory is slightly unique, and each uses different amounts of water, generalized statements can still be validly made about the relative water use of the different sources of electricity. River Network recently produced a study that looks at the issue (www.rivernetwork.org/news/burning-our-rivers-water-footprint-electricity). Wind and solar photovoltaic electricity generation use much less water than coal or nuclear or natural gas generation, hundreds of times less water.

Our current electricity markets largely treat water use as a free externality, just like the carbon or methane pollution that affects the climate. These failures to take the true costs of our energy use into account in the market continue to lead us down a path that treats our waters and our air as garbage dumps and worthless freebies. It is a short-sighted choice, and is ultimately one we canít afford.